Author Topic: Active Pitchcontrol  (Read 331786 times)

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ChrisOlson

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Re: Active Pitchcontrol
« Reply #330 on: January 18, 2013, 05:14:20 PM »
I just set up my blade carving machine to carve that airfoil and it works good.  I can sand it down to a 4412 but the 4415 seems to have a bit better torque and I can make the blades run a bit slower in the midrange and still get the power from it, then let them speed up as the wind speed increases.

I carve them with just about no pitch at the tip (maybe 1/2 degree) and about 8 degrees at the root.  They run plenty fast enough.

That's a nice Spitfire.  Now all you need is a scale model working V-12 Rolls-Merlin for it    ;D
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Menelaos

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Re: Active Pitchcontrol
« Reply #331 on: January 19, 2013, 12:23:31 AM »
found this on youtube today...

I like his work, its worth looking at his other videos as well...
I also use car hubs made by BMW for my bigger designs of active pitch control.
Might be some inspiration...at least another nice approach :-)


Max

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Re: Active Pitchcontrol
« Reply #332 on: January 19, 2013, 02:02:15 AM »
I don't know how I put my above post on this thread.
gww

Frank S

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Re: Active Pitchcontrol
« Reply #333 on: January 19, 2013, 02:49:29 AM »
found this on youtube today...

I like his work, its worth looking at his other videos as well...
I also use car hubs made by BMW for my bigger designs of active pitch control.
Might be some inspiration...at least another nice approach :-)


Max
His pitch control works nicebut I would hope that when he puts the turbine up for use he would use nylock nuts or double lock nuts or safety-wire or loktite or some means to prevent any bolting hardware for coming loose 
I live so far outside of the box, when I die they will stretch my carcass over the coffin

midwoud1

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Re: Active Pitchcontrol
« Reply #334 on: January 19, 2013, 03:40:30 AM »
Found on YouTube

 Another active pitch windmill with faster actuator response.
Istanbul . Turkeya

      http://www.youtube.com/watch?v=MWz87YH9yz4

      http://www.youtube.com/watch?v=8tozBPjSpuw
« Last Edit: January 19, 2013, 04:16:56 AM by midwoud1 »

Menelaos

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Re: Active Pitchcontrol
« Reply #335 on: January 19, 2013, 09:05:53 AM »
Nice design...but I do not like those Pedestal block bearings, also in your setup. Ball Bearings are not made for axial forces to widthstand the centrifugal forces of the blades when they spin with higher RPM. Furthermore they only have one single point of contact with the ball housing. They will wear out quickly, especially when there are additional vibration issues and the bearings hold up in one and the same position most of the time.

In my opinion, the only things that will last for a long time will be roller bearings or cylindrical roller bearings as they are made for axial forces as well and have much more contakct surface. Roller bearings in addition have the advantage that the can be lined up in case of tolerances...also slide bearings are good or a combination of them

Max

ChrisOlson

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Re: Active Pitchcontrol
« Reply #336 on: January 19, 2013, 10:40:35 AM »
In my opinion, the only things that will last for a long time will be roller bearings or cylindrical roller bearings as they are made for axial forces as well and have much more contakct surface.

Max - not totally accurate.  Roller bearings will hammer out (brinnell) due to the fact that they are required to have the rollers turning to keep them lubricated.  When they sit in one spot the lubrication "cushion" that protects the rollers from metal to metal contact with the races is not renewed and they fail prematurely.

Tapered roller bearings are the worst choice for axial loading in an application where the bearing does not turn in its design speed range.

The best choice for axial load is bronze thrust washers or bearings with thrust flanges.  The second best choice is angular contact ball bearings.  Svenska Kullagerfabriken AB (SKF) in Sweden invented them.  Sven Wingqvist's 1907 Swedish patent for the multi-row angular contact ball bearing forever changed how combination radial and axial loads are handled in machines.
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Menelaos

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Re: Active Pitchcontrol
« Reply #337 on: January 19, 2013, 10:59:19 AM »
Ok Chris, so you think that my blade bearing will hammer out as well...as it contains taper roller bearings...it is a common car hub. The turbine is not finished yet but it will turn the blades once a day to grease the rollers...

I like this setup as it is easy to build without lathe and cheap to get.

Slide bearings are probably the best choice, IGUS makes some great stuff over here and they are cheap but there are tight tolerances to keep and without a lathe the shafts will not be cheap to make which is why I did not mention them...

"The best choice for axial load is bronze thrust washers or bearings with thrust flanges."
I am not sure what you mean...google translate makes probelems here as well. Could you post a picture of an example or even of the complete setup on how you would construct the blade shaft bearing section?

Max

edit.

I think you mean this with the angular contact ball bearings...?:

http://www.ebay.de/itm/1x-Schragkugellager-3001-2RS-12x28x12-mm-NEU-/140898605990?pt=Wälz_Kugel_Rollenlager&hash=item20ce361ba6#ht_1776wt_732

If so, I think I could get replacements for my hubs or choose a different make. Some trailer hubs have those inside them but usually those are the ones that are rated for 250 or 750 Kg axles...so I am not sure if they could hold up with a blade length of 3m.

I cannot quite remember the numbers exactly but I once calculated for a given set of laminated blades that the centrifugal force of a 6m prop was something like more than 500 KG of axial force on higher rpm for something like 50 mph and I like having some room for safety...
I am not sure if such a trailler hub can handle that...

« Last Edit: January 19, 2013, 11:20:04 AM by Menelaos »

ChrisOlson

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Re: Active Pitchcontrol
« Reply #338 on: January 19, 2013, 11:28:13 AM »
A constant speed propeller hub cutaway - Hamilton aircraft propeller:



This is a hydraulic hub, operated by engine oil pressure that comes from the prop governor on the engine case and is fed to the pitch control piston thru a port in the end of the crankshaft.  While not shown in the cutaway, the root bearings are bronze (sleeve) bushings.  The oil seals are standard lip type.  The thrust bearings are angular contact ball.

Tapered roller bearings have been proven to fail in aircraft propeller hubs, although many companies have tried them.
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Menelaos

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Re: Active Pitchcontrol
« Reply #339 on: January 19, 2013, 12:14:06 PM »
chris, did u see the "edit" part in my last post?

Max

midwoud1

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Re: Active Pitchcontrol
« Reply #340 on: January 19, 2013, 12:44:58 PM »
Max.

Chris gave already a clear explaination , a combination of a thrust bearing and bronze sleeve bushing.
You can find all the thrust and radial loads in the bearing catalogues like SKF, Nachi, etc.
As you know the weight of your blade and max. Rpm. You can calculate the centrifugal force.
I have angular contact and deepgroove bearings in my flying windmill, it is a light weight 3 meter diam. prop. Running perfect.
Keep going good luck.

Rgds   - Frans -

ChrisOlson

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Re: Active Pitchcontrol
« Reply #341 on: January 19, 2013, 02:08:34 PM »
I have angular contact and deepgroove bearings in my flying windmill, it is a light weight 3 meter diam. prop.

The bearing shown in your top picture there, Frans, is a called a deep groove angular contact ball bearing.  They are rated for 100% axial loading and radial loading.  They come in single row (show in the photo) and dual row, as well as self-aligning type (covered by Sven Wingqvist's 1907 Swedish patent).  They are the absolute best choice for a blade hub where both axial and radial loading is applied to the bearing assembly.  That type of bearing is just about the only type used anymore in front-wheel-drive cars for the cartridge type wheel bearings.

The only way to make it stronger and more durable yet would be to use the bronze sleeve bushings and angular contact ball thrust bearings shown in my photo of the Hamilton aircraft prop hub.
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SparWeb

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Re: Active Pitchcontrol
« Reply #342 on: January 19, 2013, 10:46:18 PM »
Since this thread has drifted from Frans' question about pitch settings to the ball bearings, how about I make it worse and link up this this (similar) thread:

http://www.greenpowertalk.org/showthread.php?t=15544

...

Anyway, back to your pitch control Frans, it sounds like the 6-degree increment of pitch is enough to trigger the moment of oscillation, as I understand it now.
That represents a change in lift-coefficient by +/-0.5 or in other words about +/-30% torque if the blades are already at or near stalling.
I thought your mechanism moved the blade pitch in a progressive way, not in steps.  Perhaps I didn't understand your reply yesterday, so I'll look through your old postings about the turbine to get this straight.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
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SparWeb

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Re: Active Pitchcontrol
« Reply #343 on: January 19, 2013, 10:51:30 PM »
Well that didn't take long to find  :)
You described the pitch controller to me in your earliest posts.  It's just my memory at fault. 
At that time the pitch would change in 2-degree increments.  Have you changed this?
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

midwoud1

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Re: Active Pitchcontrol
« Reply #344 on: January 20, 2013, 10:07:07 AM »
I have several things I can adjust.
Switch trigger at max. and low rpm. (350 - 250 )
Actuator speed.by variable voltage supply.
Active time of acuator ( 1/10th sec - 60 sec ) set by software Arduino controller.
I call 1sec.time one step maybe a wrong expression.That is an progressive increment pitch of 6 degrees for now.
Depends on the active actuator time I have an angle set.
Combination of time and speed
At 12 degr.pitch ,Stall begins ,
Still have 60% of power.
Blade tip angle almost zero degrees in normal working condition.
Rgds -Frans -
« Last Edit: January 20, 2013, 10:21:00 AM by midwoud1 »


mbouwer

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Re: Active Pitchcontrol
« Reply #346 on: January 26, 2013, 07:11:52 AM »
Hey Frans,

In the park nearby we can see that in the past days big pieces of ice have been thrown off te wings.
How is the situation at your site?

Regards Rinus

midwoud1

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Re: Active Pitchcontrol
« Reply #347 on: February 05, 2013, 05:48:31 AM »
Windgenerator in high wind  12 - 15 m/sec.
Automatic feather and unfeather .
Max. Rpm. 350
Arduino controller .
Rgds. - Frans -

http://www.youtube.com/watch?v=F9AN1TdJz1A


mbouwer

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Re: Active Pitchcontrol
« Reply #348 on: March 02, 2013, 08:07:13 AM »
@midwoud,

Nice engineering,

Maybe in this way in Holland more interest in building small windturbines arises.

Regards Rinus

midwoud1

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Re: Active Pitchcontrol
« Reply #349 on: April 05, 2013, 04:58:14 PM »
Blade pitch mechanism.
Lineair actuator (adjustable stroke )
Manual switch forward / reverse
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midwoud1

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Re: Active Pitchcontrol
« Reply #350 on: April 11, 2013, 11:55:53 AM »
Yearly check up windturbine  11-04-2013.
Mechanical and electrical.
All looking good.
A little paint on the blades.
Teflon spray oil on the gear.
Minor adjustment gear-wheels.
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midwoud1

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Re: Active Pitchcontrol
« Reply #351 on: April 20, 2013, 04:11:08 PM »
Lineair actuator 3  test. Variable blade pitch.
It has a cordless drillmotor 12 VDC with a planetary gear ,two stage 36 : 1
Gear has hi-grade plastic satellite wheels (China ??) all the low voltage drills have it.
Output shaft 550 Rpm ,threaded rod M8 increment 1,25 mm p. turn
Stroke 100 mm / 10 sec. with adjustable end switches.
Cheap and strong system.
 - Frans -

http://www.youtube.com/watch?v=rckwnQrHtOs

mbouwer

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Re: Active Pitchcontrol
« Reply #352 on: April 21, 2013, 04:53:13 PM »
midwoud,

do you think it's possible to make things more compact?

rgds Rinus

midwoud1

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Re: Active Pitchcontrol
« Reply #353 on: April 22, 2013, 12:05:31 PM »
Rinus.

It is a test setup , total lenght is 480 mm
Can be made compact to 330 mm with 1/2 inch timingbelt.

Rgds - Frans -

midwoud1

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Re: Active Pitchcontrol
« Reply #354 on: April 27, 2013, 01:28:59 PM »
Yaw drive.

Test set-up.
Cordless drill-motor , wormgear 100 : 1 ,Chain sprocket 3,5 : 1 .
360 degr. in 60 seconds. Windvane micro switch activate.

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http://www.youtube.com/watch?v=ga6yLKOq608


electrondady1

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Re: Active Pitchcontrol
« Reply #355 on: April 27, 2013, 02:37:34 PM »
i admire the way you re purpose and re task commonly available mechanisms for your your enhancements

mbouwer

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Re: Active Pitchcontrol
« Reply #356 on: April 28, 2013, 04:06:50 AM »
just replacing the tail by a servo-actuating mechanism.
nice development.

rgds Rinus

midwoud1

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Re: Active Pitchcontrol
« Reply #357 on: April 28, 2013, 08:01:21 AM »

midwoud1

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Re: Active Pitchcontrol
« Reply #358 on: June 19, 2013, 04:41:20 PM »
Windturbine Cam Blade-pitch.
200 Rpm , 6 Amp , 24 Vdc , 4 m/sec.

- Frans -


http://www.youtube.com/watch?v=69HZD4rG__U     






SparWeb

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Re: Active Pitchcontrol
« Reply #359 on: June 24, 2013, 03:05:19 PM »
Fantastic, Frans,
Thank you for doing so much work to make such a fun video.
And such a clear demonstration of your effective system.

That must be your house, showing off those PV panels!
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

midwoud1

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Re: Active Pitchcontrol
« Reply #360 on: June 24, 2013, 03:44:10 PM »
Sparweb thanks. I made the video with a very cheap carcam € 29 incl.shipping.
Had to have special weather conditions : not to much wind ( noisy microphone )
Not to much sun ( over exposure )
The advantage of a carcam , it starts as soon as you put 12 volt on it.
SD card memory 16 Mb  8 hours.
Tower lower and raise 30 minutes.
The house with the solar panels is my neighbors (grid tied)
More will follow.
- Frans -

SparWeb

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Re: Active Pitchcontrol
« Reply #361 on: June 25, 2013, 01:51:59 AM »
...More will follow.
- Frans -

And looking forward to it!
No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
System spec: 135w BP multicrystalline panels, Xantrex C40, DIY 10ft (3m) diameter wind turbine, Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024
www.sparweb.ca

kitestrings

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Re: Active Pitchcontrol
« Reply #362 on: June 26, 2013, 12:31:09 PM »
frans,

Very cool!  I like the camera angle on this one.  it's like riding the thing (without the risk).  Thanks for sharing.

~kitestrings